On Thursday, Yoon was to be questioned about allegations of electoral fraud, but according to the prosecutors, this could not be carried out due to his strong refusal.
The suspect refused to let himself be arrested while lying on the floor without wearing his prison clothes, said prosecutor Oh Jeong-Hee.
Yoon is said to have been wearing a sleeveless shirt and the prison's underpants at the time, according to the prosecutors. For security reasons, they refrained from using physical force, but Yoon is said to have been informed that this may be used in the next attempt.
Yoon's lawyers claim at the same time that the temperature in the cell approaches 40 degrees, and that the former president suffers from several underlying conditions that make it difficult to cooperate fully in the investigation. They accuse the prosecutors of showing a lack of respect and of having turned the press conference into "a scene for personal humiliation".
The former president has been charged since before for leading a suspected attempt at a coup d'état in South Korea, after he declared a short-lived state of emergency in the country in early December and sent the military to parliament. In July, he was arrested for the second time and is now in a solitary cell.
He denies the allegations and has insisted that he, as head of state, had the authority to introduce martial law.
